These test vectors are extracted from
https://github.com/BLAKE2/BLAKE2/blob/master/testvectors/blake2-kat.json

All json objects that contain '"hash": "blake2s"' have been extracted and
saved in blake2s_test_vectors.json.

Using the blake2s.awk program on blake2s_test_vectors.json, we can
generate v code that can initialize an array of TestVector structures.

awk -f blake2s.awk blake2s_test_vectors.json >test_vectors.v

Copy the contents of test_vectors.v into ../blake2s_test.v
